NU 643 Exam 1 V3 | NU 643 Advanced
Psychopharmacology | Actual Q&A with
Rationale (NU643 Exam 1) | Regis
University
1. Which Cytochrome P450 enzyme is significantly induced by cigarette smoking, potentially
lowering the serum levels of certain antipsychotics like clozapine and olanzapine?
A. CYP 2D6
B. CYP 2C19
C. CYP 3A4
D. CYP 1A2
Answer: D
Rationale: Polycyclic aromatic hydrocarbons in cigarette smoke induce the CYP 1A2
enzyme. This induction results in increased metabolism of drugs that are substrates of this
enzyme, such as clozapine and olanzapine. Consequently, if a patient stops smoking, the
enzyme activity decreases, which may lead to toxic levels of the medication if the dose is
not adjusted.
2. How many half-lives are generally required for a drug to reach steady-state plasma
concentrations in the human body?
A. 1 to 2 half-lives
,B. 3 half-lives
C. 7 to 10 half-lives
D. 4 to 5 half-lives
Answer: D
Rationale: Steady state is achieved when the rate of drug administration equals the rate of
drug elimination. It typically takes between four and five half-lives to reach this
equilibrium regardless of the dose. Understanding this concept is vital for PMHNPs to
properly time laboratory monitoring and clinical assessments.
3. A patient taking a Monoamine Oxidase Inhibitor (MAOI) consumes a meal high in tyramine
and subsequently presents with a severe headache and hypertension. This reaction is
primarily caused by:
A. Release of stored norepinephrine leading to vasoconstriction
B. Excessive serotonin release in the gut
C. Inhibition of dopamine reuptake in the synapse
D. Blockade of alpha-2 adrenergic receptors
Answer: A
Rationale: Tyramine acts as an indirect sympathomimetic amine that displaces
norepinephrine from storage vesicles. In the presence of MAOIs, tyramine is not properly
metabolized in the gut, leading to a massive release of norepinephrine. This results in the
, classic hypertensive crisis characterized by extreme blood pressure elevation and potential
cerebrovascular events.
4. Which antidepressant is known for having a very long half-life of its active metabolite,
potentially lasting up to 2 weeks?
A. Fluoxetine
B. Paroxetine
C. Sertraline
D. Escitalopram
Answer: A
Rationale: Fluoxetine has a unique pharmacokinetic profile due to its active metabolite,
norfluoxetine, which has a half-life of 7 to 15 days. This long half-life provides a ‘built-in’
tapering effect that reduces the risk of discontinuation syndrome. However, it also requires
a longer washout period when switching to a contraindicated medication like an MAOI.
5. The mechanism of action for Benzodiazepines involves the positive allosteric modulation of
which receptor?
A. 5-HT1A receptor
B. GABA-B receptor
C. NMDA receptor
D. GABA-A receptor
Psychopharmacology | Actual Q&A with
Rationale (NU643 Exam 1) | Regis
University
1. Which Cytochrome P450 enzyme is significantly induced by cigarette smoking, potentially
lowering the serum levels of certain antipsychotics like clozapine and olanzapine?
A. CYP 2D6
B. CYP 2C19
C. CYP 3A4
D. CYP 1A2
Answer: D
Rationale: Polycyclic aromatic hydrocarbons in cigarette smoke induce the CYP 1A2
enzyme. This induction results in increased metabolism of drugs that are substrates of this
enzyme, such as clozapine and olanzapine. Consequently, if a patient stops smoking, the
enzyme activity decreases, which may lead to toxic levels of the medication if the dose is
not adjusted.
2. How many half-lives are generally required for a drug to reach steady-state plasma
concentrations in the human body?
A. 1 to 2 half-lives
,B. 3 half-lives
C. 7 to 10 half-lives
D. 4 to 5 half-lives
Answer: D
Rationale: Steady state is achieved when the rate of drug administration equals the rate of
drug elimination. It typically takes between four and five half-lives to reach this
equilibrium regardless of the dose. Understanding this concept is vital for PMHNPs to
properly time laboratory monitoring and clinical assessments.
3. A patient taking a Monoamine Oxidase Inhibitor (MAOI) consumes a meal high in tyramine
and subsequently presents with a severe headache and hypertension. This reaction is
primarily caused by:
A. Release of stored norepinephrine leading to vasoconstriction
B. Excessive serotonin release in the gut
C. Inhibition of dopamine reuptake in the synapse
D. Blockade of alpha-2 adrenergic receptors
Answer: A
Rationale: Tyramine acts as an indirect sympathomimetic amine that displaces
norepinephrine from storage vesicles. In the presence of MAOIs, tyramine is not properly
metabolized in the gut, leading to a massive release of norepinephrine. This results in the
, classic hypertensive crisis characterized by extreme blood pressure elevation and potential
cerebrovascular events.
4. Which antidepressant is known for having a very long half-life of its active metabolite,
potentially lasting up to 2 weeks?
A. Fluoxetine
B. Paroxetine
C. Sertraline
D. Escitalopram
Answer: A
Rationale: Fluoxetine has a unique pharmacokinetic profile due to its active metabolite,
norfluoxetine, which has a half-life of 7 to 15 days. This long half-life provides a ‘built-in’
tapering effect that reduces the risk of discontinuation syndrome. However, it also requires
a longer washout period when switching to a contraindicated medication like an MAOI.
5. The mechanism of action for Benzodiazepines involves the positive allosteric modulation of
which receptor?
A. 5-HT1A receptor
B. GABA-B receptor
C. NMDA receptor
D. GABA-A receptor
